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Peripheral
Looking to the Future – Next-generation Bioactive Stent-graft Technology
a report by
Yves S Alimi
Professor of Vascular Surgery, and Head, Department of Vascular Surgery, University Hospital Nord, Marseilles
Peripheral arterial disease (PAD) increases in prevalence and incidence with be treated with above-knee (AK) femoropopliteal bypasses, the majority of
advancing age, and the shifting demographics of an ageing general patients present more advanced PAD with more extensive occlusions, and
population is expected to increase the burden of PAD. Thus, there has been require bypass to arteries below the knee (BK).
an increased focus on how best to manage this burden. If intervention is
deemed necessary, surgery remains the gold standard for certain forms of Surgical Intervention
lower-extremity occlusive disease. However, endovascular therapy is gaining The autologous saphenous vein is established as the bypass conduit of
greater acceptance. choice for all such instances because of its superior clinical performance and
long-term patency compared with synthetic grafts.
2
Analysis of the
In treatment for superficial femoral artery (SFA) occlusive disease, surgery published literature showed one-year primary patency rates of 66 and 81%
demonstrates good long-term patency rates; however, surgery is associated for expanded polytetrafluoroethylene (ePTFE) and vein BK bypasses,
with greater morbidity and mortality. In comparison, while endovascular respectively. Small-diameter synthetic conduits have produced historically
intervention studies for the SFA have yet to show long-term patency, the disappointing results for BK reconstruction, especially when bypassing into
technique is associated with less morbidity and mortality. Furthermore, the an infra-popliteal target vessel.
3–5
constantly evolving field of endovascular intervention continues to
determine the best material and techniques for recanalisation of the SFA. Unfortunately, use of the patient’s saphenous veins may not be possible in
a significant number of cases because of prior use or removal, varicose vein
Management of Superficial Femoral Artery disease or small size and unfavourable anatomy. In addition, the risks of
Occlusive Disease surgery are significantly greater than the risks of an endovascular approach,
The Transantlantic Inter-Society Consensus (TASC) has classified four in terms of not only mortality but also major morbidity (prolonged
clinically important types of SFA lesion:
1
hospitalisation and delay in return to normal activities). Therefore, the
assessment of the patient’s general condition and anatomy of the diseased
• TASC type A lesions are a single stenosis ≤10cm in length or a single segment or segments becomes central in deciding which approach
occlusion ≤5cm in length. Endovascular therapy is the treatment of is warranted.
choice for type A lesions.
• TASC type B lesions are classed as: multiple lesions (stenoses or Endovascular Intervention
occlusions), each ≤5cm; a single stenosis or occlusion ≤15cm not Balloon angioplasty and subintimal angioplasty have been associated with
involving the infra-geniculate popliteal artery; single or multiple lesions high failure rates, especially with longer SFA segments.
6
Moreover, bare
in the absence of continuous tibial vessels to improve inflow for a distal nitinol stenting has demonstrated significantly higher primary patency rates
bypass; a heavily calcified occlusion ≤5cm in length; or a single versus dilatation alone of SFA lesions.
7
However, restenosis due to intimal
popliteal stenosis. Endovascular treatment is the preferred treatment hyperplasia still remains a problem with bare nitinol stenting, and patency
for type B lesions. rates remain below those of surgical intervention.
8
Patency with bare stents
• TASC type C lesions are multiple stenoses or occlusions totalling >15cm usually fails because of intimal hyperplasia throughout the stented region.
with or without heavy calcification or recurrent stenoses or occlusions Intimal hyperplasia is the outcome of smooth-muscle-cell proliferation and
that need treatment after two endovascular interventions. Although migration into the intima, as well as proteoglycan secretion. These processes
surgery is the preferred treatment for good-risk patients with type C are modulated by a complex array of events triggered soon after stent
lesions, the patient’s co-morbidities, fully informed patient preference insertion. Platelet activation and thrombus formation take place at the
and the local operator’s long-term success rates must be considered luminal wall. Acute inflammation, formation of granulation tissue and
when making treatment recommendations for type B and type C lesions. release of chemokines and oxygen free radicals occur in the wall adjacent to
• TASC type D lesions are classed as chronic total occlusions of the SFA
(>20 cm, involving the popliteal artery) or a chronic total occlusion of Yves S Alimi is a Professor of Vascular Surgery and
popliteal artery and proximal trifurcation vessels. Surgery is the treatment
Head of the Department of Vascular Surgery in the
University Hospital Nord of Marseilles. He is a Member
of choice for type D lesions.
of the Council of the French Society of Vascular Surgery,
and holds a scientific position in the Strasbourg-based
SFA occlusive disease has clinical characteristics encompassing intermittent
European Institute of TeleSurgery. Professor Alimi
founded Protomed, a society responsible for new
claudication of various degrees and critical limb ischaemia (CLI) that may
surgical and endovascular prototypes in the field of
lead to tissue loss or amputation. Recanalisation is frequently necessary to
vascular reconstructions.
relieve symptoms as well as to save limbs. Although some claudicators may
© TOUCH BRIEFINGS 2008 65
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